I reproduced the issue but still not sure that it is your situation.
Steps that I did to reproduce:
I create a simple template with a tooltip extension. (like in the attached snippet)
Add margin-top and padding-top attributes to the gantt container.
Hover the mouse over the task.
The tooltip position is wrong.
Snippet with reproduced issue(check HTML tab): https://snippet.dhtmlx.com/13cc0c18f
Is it the same issue that you have?
It appears to be a bug on our end, thank you for noticing it. I’ve already forwarded this issue to our dev team and, if you want, I will inform you when this issue will be fixed.
To avoid this problem, I could advise a workaround solution:
you could use
position: relative , with
Like in the following snippet: https://snippet.dhtmlx.com/a51251da0
If you’re having a different issue, could you reproduce it in the following snippet:
https://snippet.dhtmlx.com/13cc0c18f click the share button and send me the link?
Unfortunately, If you’re having this issue, you could meet the same problem with links positions(only in the Edge browser and our snippet tool), and a workaround solution will not fix it.
This bug is in our bug tracker, and the dev team works on a fix, unfortunately, I can’t give you an ETA for this fix.